Fuel pumping device



Oct. 18, 1932. E. A. RocKwELL FUEL PUMPING DEVICE Filed July 2. 1928 IIIIIIP i uw f/ Patented Oct. I18, 1932 UNITED STATES PATENT OFFICE FUEL PUMPING DEVICE Application led J'uly 2,

The purpose of this invention is to provide an improved construction of a pumping device for supplying fuel to the internal combustion engine. It consists in the elements r and features'of construction shown and deo scribed as indicated in the claim.

In the drawing:

Figure l is a diagrammatic view showing the relative position of the pumping device with respect to the engine with the fuel source and the carbureter on an automobile.

Figure 2 is an axial section of the pumping device, section including a connection of the pumping device with the engine.

In the structure shown in the drawing the engine is indicated at A, the fuel source at the rear of the automobile at B, the engine carbureter at C, and the pumping device in totality at D.

The pumping device comprises a casing or frame structure consisting of a part, 20, adapted to be mounted on the engine body,

' as seen at 21, and a part, 22, which is mounted on the part, 20, said parts, and 22, being formed with mated flanges, 20":L and 22a, en-

compassing cavities, 20b and 22h, in said parts respectively, and serving for clamping between the two members, 2 0 and 22, a flexible diaphragm, 25, which constitutes the movable wall of a pumping chamber which is formed by the cavity, 22h, in the part, 22. Said pumping chamber is 'connected by a pipe, 26, for receiving fuel from the fuel source, and is connected with the carbureter for supplying fuel thereto by a pipe, 27, between which and the pumping chamber there is interposed a trap, 28. Interposed in the connection of the pumping chamber with the pipe, 26, leading from the fuel source, there is provided a 40 check valve, 30, opening for inflow to the pumping chamber and 'seating against reverse flow, and between the pumping chamber and the trap, 28, there is interposed a check valve, 31, opening for outflow from the pumping chamber toward the trap and 1928. Serial No. 289,693.

seating against reverse flow. The trap chamber, 29, is adapted for the function of trapping the fuel between the pumping chamber and the carbureter by having a pipe 28, mounted in the bottomof the trap chamber for fuel flow connection from the pumping chamber beyond the check valve, 3l, said pipe extending upwardly in the trap chamberand open for discharge at the upper part of said chamber.

Outilow from the trap chamber is afforded by' a pipe, 28", mounted in the cover, 28, of the trap chamber and extending downwardly in the trap chamber and open for entrance of fuel at the lower end near the bottom of the trap chamber, the pipe, 27, being connected with said pipe, 28h, at the upper` end thereof, the cap, 28, having the boss, 28d, at which the pipe member, 28h, is connected adapted for connecting also the pipe, 27. The flexible diaphragm, 25, constituting the movable wall and pumping member of the pump chamber, 22", is normally flexed- Vinwardly in chamber-reducing direction by a spring, 35, seated at its lower end' at the 70 bottom of the cavity, 20?, in the casing member, 20, and reacting at its upper end against the under side of the diaphragm whose central area is clamped between disks, 33 and 34, limiting its flexure to the outer annular area, 25a, said disks being thus clamped to the diaphragm by a nut, 36, above the upper disk, 34, which is screwed onto a stem, 37, which is thereby secured to the diaphragm for actuating it. Said stem, 37, is provided with guide bearing at 201 in the casing member, 20, and is operated by a lever, 38, fulcrumed at 38a in the casing member, 20, and protruding from said casing member into the engine casv ing through an aperture in the latter at which the casing member, 20, is mounted, as mentioned, the lever terminating, as seen at 38%, in position for actuation by a cam, 40, on a rotating shaft of the engine.

The other end of the lever in the'casing 90 the spring, 35, and thereby yieldin member, 20, is connected with the stem, 37, by

linkage consisting, as shown, of two links, 41

and 42, pivoted together and having the lower end'of the link, 42, pivotally connected to the lever, 38, and the upper end of the link, 41, connected to the stem, 37, said links being provided with co-operating stops, 41 and 42, which prevent them from being pulled into alignment of their three pivots by the movement of the lever in the direction which might thus align said pivots, being the direction of the chamber-enlarging movement of the diaphragm, 25; by which expedient the lever, 38, is rendered incapable of actuating the stem, 37, and diaphragm, 25, in the direction of chamber-reducing movement of the diaphragm the linkage folding in that movement o the lever except under conditions under which the reaction of the spring, 35,

on the diaphragm, and thereby on the stem, 37, operates forlretracting the stem and the linkage correspondin ly to the movement-of the lever in the directlon which would otherwise tend to fold the linkage. f

From the above description of the construction it may be understood that the engine connection described operates for positive actuation of the exible diaphragm in pumpingchamber-enlarging direction for lifting the fuel by suction from the low level source; and' that the movement of the diaphragm in cham ber-reducing direction for feeding the fuel.

to the carbureter is effected by the relaction of The chamber 28 located on the outlet of the pump has several combined functions, first, it may be understood that the chamber W1ll act in the ordinary manner as a pressure or vapor dome since the chamber is closed except for the inlet and outlet connectlons and the vaporpand gases separating fromthe fuel will collect at the top of the chamber and form a body of trapped gas tending to depress the level of the fuel in the chamber belowthe top of the inlet pipe28a. The trapped aseous pressure will maintain a more uniorm and continuous iow of the fuel to the iloat chamber of the carbureter since the fluctuationsof pressure caused by the intermediate flow of the fuel from the pumping chamber to the chamber 28 will be absorbed by the body of trapped gas. Furthermore,

' the construction enablesl a more ready separation of the Yapor and gases of fuel in the pressure chamber than if the inlet connection were below or at the same level as the outlet connection. As described, the depres- 1 sion f the fuel level below the top of the inlet ipe 28',L causes the 'fuel to be delivered directy into the body of-trapped gas.

Another importantA function of having the inlet above the outlet from the chamber '28 is that the chamber acts as a trap with suicient capacity to receive the fuel which may flow back from the 'oat chamber of the carbureter due to leakage of the needle valve. Thus when the engine is stopped, if the fuel leaks back dueto the leakage at the needle valve and at the valves in the pump, the fuel level will rise in the chamber 28 to the top of the pipe 28. On starting the engine, the pump will immediately build up a pressure which will cause the trapped fuel to flow to the float chamber of the carbureter and again depress the level of the fuel below the top of the inlet pipe 28a.

.Desirably, for the purpose of holding the terminal, 3 8", of the lever, 38, in continuous contact with the cam,j40, to avoid the annoyance which would otherwise be caused by the cam coming into contact with the lever at the diaphragm from making a full feeding stroke, there is provided a spring, 39, reacting between the bottom of thecasing and the lever, 38, vfor stressing the-operating end of the lever upward, proper connection between the spring and the lever being afforded by a cap-disk, 39, at the top of the spring, and a prong, 38e, extended down from the lever seating in a depression at the center of the` l cap-disk.

I claim:

In a. fuel feed s Stem for internal combustion engines, a fue pump having check-valve controlled inlet and` outletfpassages, a plug secured to the pump body in an opening through which the outlet valve is adapted to be assembled, said plug forming a stop for said check valve and having avertical bore forming a continuation of the outlet passage from the p ump, an outletrtrap chamber carrled by said plug, an outlet feed line leadin to the carbureter connected to the top of said chamber` and tubular fuel-conducting members within -said trap chamber, one of said members being secured to said plug and delivering the fuel from the pump directly into the top ofsaid chamber and the other of said members being connected to the outlet feed line and having its intake at the bottom of said chamber.

In testimony whereof, I have hereunto Set my hand at Chicago, Ill., this4 16th day of June, 1928.

EDWARD A. ROCKWELL. 

